The present invention relates generally to an arrester assembly of novel construction for shunting over-current and over-voltage conditions present in an electrical circuit. More specifically, the invention relates to a novel cup-arrester assembly which meets a relevant industry drop impact test or standard.
The construction and operation of over-current and over-voltage arresters are well known in the relevant art. Because these arresters are necessary to protect sensitive telecommunications and related electronic equipment, such as computer modems, facsimile machines and the like, from over-voltage and over-current conditions on telecommunications lines, these arresters are quite important.
Arresters are often relatively small elements of various constructions, ranging from gas tube to carbon air gap to solid state types. The arresters are electrically connected at some point in a telecommunications line between a signal source and a piece of equipment. In this manner, it is hoped that any over-voltage or over-current conditions present in the line will encounter an arrester and be shunted to ground, thereby preventing those conditions from reaching and adversely affecting or damaging the equipment. However, the arresters must be undamaged and otherwise functionally intact in order to perform properly, as intended.
Because attesters are often relatively small in size, they can be easily dropped during manufacture and transport, or by a workman during installation. When an arrester is dropped, external forces generated upon impact of the arrestor with a surface can irreparably damage the arrester. For example, a semiconductor or solid state arrester element may fracture under the influence of the external, impact generated forces, thereby preventing the element from functioning properly. This damage is often not easily detected. This lack of detection can result in a damaged arrester being mistakenly installed. A damaged arrestor may not properly shunt over-current and/or over-voltage conditions to ground.
In an effort to minimize the possibility that a damaged, not fully functional arrester would be mistakenly installed in a circuit, there has been devised a drop impact test for arresters. Under the conditions of this test, an arrester is dropped from a height of approximately five feet onto a hard surface. The arrester is then tested to determine if it has been damaged by the forces generated by the impact with the surface. If the arrester passes the drop impact test, the arrester should be able to properly function. The novel cup-arrester assembly, constructed according to the teachings of the present invention, is intended to pass this drop impact test.